The World Wide Web ("the Web") is a collection of formatted, hypertext-based documents (often referred to as "Web pages") distributed among numerous computers around the world which are logically connected by the Internet. The Web is a valuable resource for information relating to numerous subjects, including science, technology, business, entertainment, and travel, to name just a few. Improvements in Web-related technology, such as Web browsers (software applications which provide graphical user interfaces to the Web), have made the Web accessible to a large segment of the population. Despite these improvements, however, modern Web technology still has numerous shortcomings.
Web documents commonly reference other Web documents using hypertext links. A hypertext link enables a computer user to select a word, phrase or an image (a "hypertext anchor") to signal the computer retrieve a referenced Web document located on a remote server. With Web technology of the prior art, the user generally receives no explicit information regarding the relationships between Web documents. Thus, the user generally relies upon his own "mental map" of a given portion of the Web, which he slowly forms throughout the process of navigating the Web. However, this mental map is often vague, incomplete, and inaccurate. It would be useful when browsing the Web, therefore, for a user to have a clearer understanding of the logical relationships between Web documents, so that the user can more easily navigate portions of the Web.
A common way for a computer user to determine the location of information on the Web is to search the Web using software known as a search engine. A search engine accepts search criteria entered by the user, searches the Web based on the criteria, and generally provides the user with a listing of Web documents which, at least to some extent, match the criteria. Examples of well-known conventional search engines are Yahoo!, Lycos, Alta Vista, and Excite. The search engine often resides on a remote Web site, and access to the search engine is often provided by a Web browser running on the user's computer. The search results are commonly displayed in order of the number of "hits" in each Web document, i.e., the number of terms within the document which match one or more search criteria.
One problem with this method of displaying search results is that documents with little or no relevance to the user's objective are often retrieved in a search. This is so, because the number of hits in a given Web document often has no bearing on the relevance of the document to the user's search criteria. For example, some authors of Web documents have been known to repeat certain key words and phrases multiple times out of context in a Web document, in order to attract hits from search engines. Such a document may then be found by a search engine and placed high in the list of search results, although the document may be of no interest to the user. Hence, a user is generally required to screen each document for relevance by reading the brief description of the document provided by the search engine, or by actually retrieving the document.
What is needed, therefore, is an intuitive way of graphically representing a portion of the World Wide Web. What is further needed is a technique for displaying a representation of a portion of the World Wide Web, in which the relevance of Web pages to a user's search criteria and logical relationships between Web pages are indicated to a user.